Eppendorf 5804 - Condenser Fan Regulation (Refrigerated Models); Power Supply for Major Aggregates

Centrifuge 5804/5804 R and 5810/5810 R
10 Descriptions
10-6 Descriptions
Condenser fan regulation (only refrigerated version)
A condenser is installed in the refrigeration circuit which is used to distribute the heat from the
compressor to the environment. Additionally the condenser is supplied with cooling air by a fan.
The fan regulation is done phase-controlled. This is done by a solid state relay (TRI1) which influences
the voltage at the fan and is controlled by the processor. In this application there are only two steps; full
load during the run and fixed load in stand-by mode.
The necessary phase analysis (D1, R3, OK1, R4) of the mains voltage is done by means of the phase
analysis circuit. D1 suppresses the negative half wave and the positive half wave is switched by the
opto-coupler onto a trigger. This generates a rectangular signal, which is used by the processor to
control the rotational speed of the fan.
Power supply for the refrigerating aggregate, the motor fan (lifting magnet) and the converter
These 3 aggregates operate with the mains voltage. For the individual aggregates the power is supplied
in the following way:
– the refrigerating aggregate via relay K5
– the converter via relay K3 and K4
– the motor fan (refrigerated version) via relay K6
– the lifting magnet (non-refrigerated version) directly from pin 15 and 16 of the IC7
All relay contacts are equipped with a radio shielding capacitor to minimize sparks when switching off.
On the refrigerating aggregate relay an RC circuit (R2, C7) is used for this purpose.
Converter interface
The communication between the control and the converter is done on the basis of a serial data
transmission (RS232). This makes it possible to change the converter parameters during a run to achieve
an optimal run of the centrifuge. During a run telegrams are constantly exchanged, in this way a
malfunction of the converter can be immediately analyzed.
The data input to the converter is done by port 6.2 and the data output from the converter is done by
port 6.1.
Additionally a release signal (PORT 6.4) is transferred to the converter which reports its readiness to
PORT 6.5.
The connection is done by plug connector X9.
MSTM/KW/0408